The invention is in the field of circular lamp units, such as screw-in units having a circular fluorescent lamp and a ballast.
Various types of screw-in fluorescent lamp units have been devised, for taking the place of incandescent lamps in ceiling sockets and in table lamps and floor lamps, and are economical to operate and conserve electrical energy because they consume less than half the electrical energy than incandescent lamps for the same brightness. U.S. Pat. No. 4,258,287 to Frederick Hetzel and U.S. Pat. No. 4,278,911 to Rudolph Metoff each discloses a screw-in central hub containing a ballast, and a replaceable circular lamp assembly including a circular bulb and spokes, positioned on the hub. U.S. Pat. Nos. 4,161,020 to Miller; 2,525,022 to Dupuy; 3,059,137 to Reaves; 2,534,956 to Pistey; and 2,534,955 to Dazley disclose other typical techniques for holding a circular lamp bulb, in which the support arms are hinged or slotted.